This invention relates generally to clutch mechanisms. In particular, it relates to clutches of the two-way overrunning type.
Known clutch devices of this type generally provide a pair of spaced clutch races and a plurality of wedging elements supported by a cage intermediate the races. The wedging elements are rotationally displaceable relative to the races, and are movable into and out of wedging engagement therewith. Such a clutch device is disclosed in U.S. Pat. No. 3,055,471 wherein drag shoes are in frictional contact with the clutch housing, which drag shoes are connected with the cage in such a manner as to bias the wedging elements. Resilient means of some sort is provided for biasing the drag shoes toward frictional contact with the clutch housing. However, no provision is made for controlled reduction of the force of this frictional contact under dynamic conditions, or for controlled increase under static conditions.
Other known clutch devices of this type include torsion springs wrapped around the clutch housing or an element associated therewith to establish the frictional contact which serves to bias the wedging elements. Such a clutch device is disclosed in U.S. Pat. No. 3,380,563 wherein a torsion spring provides frictional contact with the clutch housing in order to bias a system of rollers. Upon rotation, the cage picks up a portion of the torsion spring and spreads it so as to reduce the force of this frictional contact. However, the arrangement provides for a single reaction point which is neither balanced nor centered. This creates the possibility of cocking the roller cage, resulting in undesirable binding of the rollers.